Is my generator a 6 volt or 12 volt

[oldford]

The car I have has a 12 volt battery. I'm not sure if it was done right. Battery is not charging. I'm trying to figure out if the generator is a 6 or 12 volt. Ther are no markings on it. Took it to an electrical shop and they checked it and said it is working fine. Said he did not know what voltage it is for. He was busy so he probably just said that to get me out of his shop. I looked on line and it stated that if I check the ohms between the field and armature that would tell me. If it is 6 ohms are below it was a 6 volt and if higher it could be a 12 volt. I did that and it was around 16 ohms. Does that sound right.

[hueyhoolihan]

it's my understanding (...can always be wrong...) that generators create current of various voltages depending on the speed at which they run (RPM). slow speeds create lower voltage than higher speeds. so they are not directly suited to charge a battery that needs a steady voltage.

and it's the voltage regulator's (voltage for it is usually marked on teh front panel) job to massage and restrict the various voltages from the generator such that it can charge the battery.

IOW the battery and voltage regulator much match in their respective voltages. a 6v battery with a 6v regulator and a 12v battery with a 12v regulator.

[koates]

The gauge (diameter) of the wire used in field coils and also the armature are a different between 6 & 12 volt generators. 6 volt is a larger gauge wire. Regards, Kevin.

[fredM]

I would take my voltmeter and measure volts. Turn on the lights, heater on high. see what it says. But if you only take short trips, it will be hard to keep the system charged. Also, if your light bulbs are 6 volt they would have burned out right away.

[Tim Ayers]

While running, use a volt meter and place the positive on the positive stud and negative on the negative stud found towards the back end of the generator. If running well, a 6V will put out approx. 7.5 +/- and a 12V will put out approx. 13.5 +/-. You can also check the voltage at the starter solenoid.

While running, also use the volt meter to check what the battery is reading.

Once confirmed what voltage it is and it doesn't check out, the problem is somewhere else down the line and I'd check the voltage regulator after checking the generator. Could be a bad battery too.

[flathead4rd]

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What are the light bulbs in the car. Might get an idea from them.

[oldford]

Bad battery. Last week I took the battery to Oriley's for charging and they said it was alright. After reading this thread I decided to take it to a battery shop and they said it was bad, would not hold charge. Using the new battery the amp gauge shows it charging a little but only on a high RPM. When idling amp gauge is in the negative zone. I think on a model A generator if you wanted to increase the charge you could move one of the brushes. Not sure if that would work on this generator. Thanks for all the info. Will check everything tomorrow.

[hueyhoolihan]

IME, it's not unusual for a batter using generator (not alternator) based charging system to be discharging a small amount when the engine is at idle. especially so at night with the headlights on.

i've had success testing the charging system using a multimeter on a running car. i connect the multimeter's connecters to the battery posts to validate what's what as regards charging under various conditions.

[ndnchf]

What year car? 2 or 3 brush generator? Please post clear photos of your generator.

[oldford]

It's a 2 brush

https://www.fordbarn.com/forum/attac...1&d=1751591029

[petehoovie]

Originally Posted by oldford

It's a 2 brush

https://www.fordbarn.com/forum/attac...1&d=1751591029

[ndnchf]

That is a 3-brush generator that had been converted to 2-brush. Look at the remote voltage regulator. It should be marked either 6 or 12 volts.

[oldford]

I had a dream. No, not that dream. Henry said get rid of that 12 volt and go back to 6 volt. So that is what I'm going to do. Get rid of the battery, resistor, generator, voltage regulator and blubs. Never like that 12 volt any way but the car was to good of a deal to pass up. Thanks everyone for your help. Will probably be asking more questions when I get the 6 volt system going.

[ndnchf]

Contrary to the many naysayers, there is nothing at all wrong with the 6 volt system. It works just fine on an original car. That being said, I have restored flathead V8 generators available if you need one.

Steve

[hueyhoolihan]

just now converting my new-to-me '41 deluxe back to 6v from 8V!

so far so good. needed new 6v battery and 00 battery cables and new 6v voltage regulator. the regulator that came with the car, although sporting a badge on the front claiming to be a Bosch U.S.A 6v regulator, when tested proved to be providing 9-10v to charge the 8v battery, which is about right to charge it, meaning the previous owner had had it tweaked to work properly.

goodness knows what damage had been done to the generator, coil. the points and condenser were shown to have been overheated and, and so failed. i replaced the starter solenoid too, just as a precaution. i'm still in the process of examining whatever else may need to be addressed.

[petehoovie]

Originally Posted by ndnchf

Contrary to the many naysayers, there is nothing at all wrong with the 6 volt system. It works just fine on an original car. That being said, I have restored flathead V8 generators available if you need one.

Steve